Reaktion #63841

Reaktionsgleichung

2-propanone CO2

methyllithium

2,6-dichloro-α-(4-chlorophenyl)-4-(4,5-dihydro-3,5-dioxo-1,2,4-triazin-2(3H)-yl)benzeneacetyl chloride

ammonium chloride

→

2-[3,5-dichloro-4-[1-(4-chlorophenyl)-2-oxopropyl]phenyl]-1,2,4-triazine-3,5(2H,4H)-dione

Ausbeute 18.8%

Lösungsmittel

tetrahydrofuran

1,1'-oxybisethane

tetrahydrofuran

water

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.ADDITIONUpon complete addition
2. 2
   workup.STIRRINGstirring
3. 3
   workup.ADDITIONwas added dropwise during a period of 30 minutes at -65° C
4. 4
   workup.STIRRINGUpon completion, stirring
5. 5
   workup.WAITwas continued first for 2 hours at -60° C.
6. 6
   workup.WAITfor 1 hours at -20° C
7. 7
   Sonstige(exothermic reaction)
8. 8
   FiltrationThe precipitate was filtered off and from the filtrate
9. 9
   Sonstigethe organic layer was dried
10. 10
    Filtrationfiltered
11. 11
    Sonstigeevaporated
12. 12
    SonstigeThe residue was purified three times by column chromatography over silica gel
13. 13
    workup.ADDITIONa mixture of trichloromethane and methanol (95:5 and 98:2 by volume)
14. 14
    workup.ADDITIONa mixture of trichloromethane and ethyl acetate (92.5:7.5 volume) as eluents
15. 15
    SonstigeThe pure fractions were collected
16. 16
    Sonstigethe eluent was evaporated in vacuo
17. 17
    workup.STIRRINGThe residue was stirred in acetonitrile
18. 18
    FiltrationThe product was filtered off
19. 19
    Waschenwashed with 2,2'-oxybispropane
20. 20
    Sonstigedried

Vorschrift

To a stirred and cooled (-70° C., 2-propanone/CO2 bath) solution of 5.7 parts of copper(I) iodide in 67.5 parts of tetrahydrofuran were added dropwise 37.5 parts of a methyllithium solution 1.6M in 1,1'-oxybisethane during a period of 15 minutes under nitrogen atmosphere. Upon complete addition, stirring was continued for 30 minutes at this low temperature. A mixture of 4.45 parts of 2,6-dichloro-α-(4-chlorophenyl)-4-(4,5-dihydro-3,5-dioxo-1,2,4-triazin-2(3H)-yl)benzeneacetyl chloride and 22.5 parts of tetrahydrofuran was added dropwise during a period of 30 minutes at -65° C. Upon completion, stirring was continued first for 2 hours at -60° C. and then for 1 hours at -20° C. A saturated ammonium chloride solution in water was added dropwise (exothermic reaction). The precipitate was filtered off and from the filtrate, the organic layer was dried, filtered and evaporated. The residue was purified three times by column chromatography over silica gel: twice using a mixture of trichloromethane and methanol (95:5 and 98:2 by volume) and then a mixture of trichloromethane and ethyl acetate (92.5:7.5 volume) as eluents. The pure fractions were collected and the eluent was evaporated in vacuo. The residue was stirred in acetonitrile. The product was filtered off, washed with 2,2'-oxybispropane and dried, yielding 0.8 parts (18.8%) of 2-[3,5-dichloro-4-[1-(4-chlorophenyl)-2-oxopropyl]phenyl]-1,2,4-triazine-3,5(2H,4H)-dione; mp. 208.4° C. (intermediate 42).

Quelle